1. Field of the Invention
The present invention relates to radio data communication systems which transmit data from a semi-fixed terminal to a mobile terminal.
2. Background Art
Recently, personal computers have remarkably spread and the functions of portable personal computers have improved. Articles usable instead of regular personal computers have been developed and are easily available commercially. The portable personal computers are small-sized and lightweight and are convenient to take outdoors to go out, for example, on a business trip, but its memory capacity and display screen are small, so that a large amount of data can not be stored and displayed. As a result, as the case may be, necessary data is required to be downloaded from a stand-alone personal computer in the office and to use it, as required.
Recently, electronic mail using a personal computer has been used successfully. Generally, even when the user of the electronic mail is away from his office, for example, on a business trip, he needs access to his electronic mail very frequently. In such a case, transfer of an electronic mail received by a stand-alone personal computer to his portable personal computer improves productivity. However, at present, there are no methods of transferring data such as an electronic mail automatically from the stand-alone personal computer to a portable personal computer.
As described above, in the conventional bidirectional radio data communication system, the portable personal computer is completely independent of the stand-alone personal computer. There are no functions of receiving data such as an electronic mail between the stand-alone type personal computer and a portable personal computer at a remote place, so that a complicated manipulation by the user is required each time the communication is required. Mistakes in the manipulation are likely to occur and the manipulation is time consuming.